T h duff



March 13, 1945.

T H DUFF LIQUEF'IED HYDROCARBON GAS STORAGE AND DISPENSING SYSTEM Filed Oct. 23, 194.1

2 Sheets-Sheet l [/v VEN T012 flrmeMe-r T H DUFF March 13, 1945.

LIQUEFIED H YDROGARBON GAS STORAGE AND DISPENSING SYSTEM Filed 001;. 25. 1941 2 Sheets-Sheet 2 [N VEN TOE THDUFF BY a 2 A 7 Hr TOENEY gle member, it

the service line leading from the. tank to the house or other place of consump 1 the porized gas.

While the will readily be seen that said housing may also be made in two sections, one section being secured to the outer shell l1 and extending upwardly therefrom, and the other section being located in the inner shell l6 and aligned with the first section; It is also to be noted that the housing may be located near the end or the tank It to facilitate fabrication of the plan.

The usual cur -box or housing 21 may be installed for protecting the control devices and other connections extending above the tank, if desired.

A U-shaped vent tube 28 has one arm 29 extending upwardly axially within the valve chamber 22 to a point above the top of the tank l0, while its other arm 30 extends upwardly within the inner shell it to a point near its top, as is clearly shown in Figure 1. This vent tube provides communication between the vapor area of the storage tank and the valve chamber 22 for a purpose which will be hereinafter explained.

An elongate fioat'body 3!, closed at it upper end, is freely slidable within the valve chamber. The float body has an axially disposed reduced sleeve 32 secured therein and spaced from the inner wall of said body. .The sleeve terminates short of the upper end of the float body and an annular closure plate 33 is secured, by welding or otherwise, between the upper end of this sleeve and the inner wall of the float body, whereby an annular float chamber 34 is formed thereby.

The lower end of the sleeve 32 is also terminated short of the lower end of the float body, and the lower end portion of the float body has an inwardly directed flange forming a reduced opening 35 at the lower end of the bore of said body. I

As is clearly shown in Figure 1, the float sleeve 32 is freely slidable over the arm 29 of the vent tube, and is spaced therefrom to form a fiow passage therebetween. Thus, vaporized gas entering the arm 30 of the vent tube may flow through the tube into th bore of the float body and downwardly within said body between the outer surface of the tube arm 29 and the bore of the sleeve 32 to the opening 35 at the lower end of the float body, through which it will enter the valve chamber 22.

In operation, the tank is filled with liquefied hydrocarbon gas in the usual manner through the filler inlet pipe ii. The liquid level within the tank will rise and the liquefied gas will flow through the orifices l9 into the secondary chamber between the inner and outer shells of the tank, and will also enter through the opening or port 23 into the lower portion of the valve chamber 22, and will find a level in all three chambers.

Due to the fact that the liquefied gas in the secondary chamber i8 i in close heat exchanging relationship with the surrounding earth, vaporization of such gas will take place more rapidly than in the other chambers, and as a result, the space above the liquid in the secondary chamber and the valve chamber will be filled with the vaporized gas under increased pressure. The liquid in these chambers will, therefore, be forced back through the openings or port 23 and the orifices it into the main storage space in the inner shell it, since the vaporized gas cannot pass from the secondary chamber and the valve chamber into the inner shell.

housing 2i has been shown as a sinthe vaporized gas,

As the vaporized gas is drawn off through the service line, more liquefied gas enters the secondary chamber through the orifices l8 and is quickly vaporized due to the amplified area of contact and relatively thin volume which the liquid takes in the secondary chamber.

It is pointed out that the float body 3! is buoyantly supported upon the liquefied gas which is present in the lower portion of the valve chamber 22, since the fioat chamber 34 together with which has travelled through the vent tube 28 into the upper end of the float body and the float sleeve 32, are trapped in the float body by liquefied gas which has entered the lower end of the float body through the opening 35. Due to this liquid seal formed around th lower end of the float body, the vaporized gas which is in the inner shell i6 cannot pass through the vent tube into the valve chamber, so long as the lower end of the float body is below the liquid level within the inner shell.

In the event that the supply of heat which, transferred from the surrounding earth, is vaporizing the gas in the secondary chamber is lessened for any reason, or if the rate of withdrawal of the vaporized gas through the outlet 25 is sumciently increased, the level of the liquefied gas in the secondary chamber will be raised. As the liquefied gas rises in the secondary chamber, more surface of the liquid is-exposed to the heat of the earth, due to the shape of the chamber, and, consequently, there is an increase in the rate of vaporization. Such increase in the vaporization rate will ordinarily be ample to take care of the increased demand for vaporized gas.

If, however, the rate of vaporization of the gas in the secondary chamber is not sufilcient to take' care of the large withdrawal of the gas through the outlet, then the liquefied gas level in the said secondary chamber will rise until such liquefied gas flows through the openings 24 to Join the liquefied gas which has risen equally in the valve chamber 22. When this occurs, the float body 3| will naturally be elevated with the increased liquid level in the valve chamber, and, when the lower end of the body is raised above the liquid level in the inner shell IS, the gas which is trapped in the upper portion of said inner shell will travel through the U-shaped vent tube 28 and downwardly through the float sleeve 32 and outwardly through the opening 35 at the lower end of the float body into the valve chamber, from which it will be withdrawn through the outlet 25 into the service line to the house.

Thus it will be seen that vaporized gas from the main storage space within the inner shell is being utilized to supply the heavy demand and is supplementing the supply from the secondary chamber l8, thereby considerably increasing the supply.

When the period of heavy withdrawal has passed, or when the temperature condition which caused the loss of heat application to its outer shell has passed, the vaporized gas in the valve chamber will force the liquefied gas level downwardly in the secondary chamber and in the valve chamber. As the level is lowered, the fioat body 3| will follow the liquid level downwardly in the valve chamber, whereupon the gas vapor which has been flowing out of the inner shell through the vent tube will be again sealed off by the formation of a liquid seal around the lower end of the fioat body as the body's lower end moves below the liquid level in the inner shell.

The system will then operate in the usual manner first described until another period of heavy withdrawal or loss of heat energy causes the repetition of the cycle just described.

It is to be noted'that the large space within the float body below the lower end of the sleeve 32 prevents liquefied gas from rushing into the float body and upwardly through the sleeve into the vent tube before such liquefied gas could flow outwardly from the valve' chamber through the opening or port 23 at the lower end of the housing. Also, the enlarged space within the float body above the upper end of the sleeve serves the same purpose when the float body is in its completely lowered position. Presence of liquefied gas in the vent tube would inhibit the functioning of the device until such liquefied gas had vaporized. The locationof the bend in the vent tube at the lower portion of the tank serves to expose any liquefied gas which might accumulate in the tube.

to the higher temperature present at that depth, and thus to assure vaporization of such accu mulated liquefied gas.

It will be seen that I have provided, in the above system, a secondary chamber for presenting the liquefied gas to the action of the heat of the surrounding earth over an amplified area of contact, thereby increasing the rate of vaporization in a simple, readily manufactured heat exchanger, that I have ,also provided a system wherein the liquefied hydrocarbon gas is drawn from storage into the heat exchanger in a liquid form, and that I have provided means for positively controlling the flow therefrom, so that no liquefied gas can get into the service lines. Thus, I have provided a system which utilizes the mixed butane and propane of the ordinary commercial mixtures rather than drawing ofl the lighter propane faster than the heavier butane is drawn ofi, providing a more uniform heat value fuel by withdrawing the liquid mixture and vaporizing it. I have also provided a means of utilizing the gas from above the liquefied gas in the main storage in case of heavy withdrawal to supplement the regularly vaporized supply from the secondary chamber. This system is also a safer system because none of the liquid can enter the service line leading-t the house.

It is tobe noted that I have provided an improved control device for the gas which is vaporized, wherein there is formed a liquid seal for excluding the gas vapor from the main storage tank until the use of such gas is desired. Thus, the valve is simple and easily and cheaply manufactured, and wear which would be, present in valves having material forming contacting seats in the usual manner is substantially eliminated. The cap at the upper end oi the valve housing ill may be secured by screw-threads or other releasable means so as to permit its removal, whereby the float body may be inspected, repaired and replaced, if desired.

Obviously, the bouyancy of the float 3! may be changed by varying the size of the element or of the float chamber 30 therein. Also, the weight and length of the float body may be altered to effect opening of the vent tube 28 to permit withdrawal of vaporized gas from the main storage or inner shell, if desired.

or course, many variations of the invention are possible. I have, however, illustrated in Figures 5 and 6 a modified form of the invention.

'wlth aseoondary chamber ii at oneend. A

liquefied gas inlet pipe 52 provides communication between the lower portion of the main tank 50 and the secondary tank, and this pipe may extend to any suitable elevation within the said secondary chamber to control the liquid level therein so as to maintain a large amount of liquid in contact with the heat exchanging walls of the secondary chamber. mounted in the upper portion of the secondary chamber and has an upwardly directed arm 54, for the same purpose as the arm 29 of the vent tube 28 of the first form. This tube serves the same purpose as the aforesaid vent tube 28, in

' that it provides communication between the vapor space of the main storage tank and the secondary chamber. A valve float 55 having a sealing element 56 of Neoprene or other suitable material is positioned on the upper end of the arm b t for controlling the admission of the vaporized gas from the tank 50 into the secondary chamber and acts in substantially the same manner as the valve or float body 3| of the first form of the invention.

Ordinarily, gas is formed from the liquefied gas in the secondary chamber 5! and is withdrawn through an outlet 56 at the upper end of the chamber into the service line. When, however, there is a heat loss or an extremely heavy withdrawal of vaporized gas through the outlet, the level of the liquefied gas will rise in the secondary chamber until it floats the valve 55. .When the valve is lifted, the vapor in the main storage tank 50 is permitted to flow from the tank into the secondary chamber through the inlet tube 53, to supplement the gas vaporized in the secondary chamber and thus to satisfy the demand.

placed in the house cellar or in other special buildings or housings above ground. In every case, the housing or building for the tank may utilize earth, air, water, steam, or any other suitable substance as the heat source for causing vaporization of the liquefied gas.

The above description of the invention is explanatory only, and changes in details of the construction's illustrated may be made by those skilled in the art, within the scope of the appended claims, without departing from the spirit of the invention. i

What I claim and desire to secure by Letters Patent is:

1. A liquefied gas storage and dispensing system including, a storage tank for holding liquefied gas under pressure, a secondary vaporizing chamber in heat exchanging relationship withthe surrounding medium, means for admitting liquefied gas from the storage tank into said secondary chamber for vaporization therein, a valve chamber having communication with the secondary chamber for receiving vaporized gas therefrom and having a service outlet, and means establish- 1 ing communication between the vapor space of the storage tank and said valve chamber normally closed by a liquid column of the stored In Figure 5, I have provided a storage tank 50 1| liquefied gas to prevent admission of vaporized A vapor inlet tube 53 isgas from the vapor space of said storage tank to said valve chamber, said last-named means being operable to admit suchvaporized gas under predetermined conditions of withdrawal of vaporized gas from the secondary chamber in excess of its vaporizing capacity.

2. A liquefied gas storage and dispensing system including, a storage tank for holding liquefied,gas under pressure, a secondary vaporizing chamber in heat exchangingrelationshi-p with the surrounding medium, means for admitting liquefied gas from the storage tank into said secondary chamber for vaporization therein, a valve chamber having communication with the secondary chamber for receiving vaporized gas therefrom and having a service'outlet, means establishing communication between the vapor space of the storage tank and said valve chamber, means for admitting liquefied gas from the storage tank to said valve chamber, and a float valve in the valve chamber and actuated by the liquefied gas in said valve chamber for controlling the admission of vaporized gas from the vapor space of said storage tank to said valve chamber.

3. A liquefied gas storage and dispensing system including, a storage tank for holding gas under pressure, a secondary vaporizing chamber 7 surrounding said tank and in heat exchanging relationship with the surrounding medium, means for admitting liquefied gas from the storage tank into said secondary chamber for vaporization therein, a valve chamber having communication and afloat valve in the valve chamber and actu-- ated by the liquefied gas in said chamber for controlling admission of the vaporized gas from the vapor space of said storage tank to said valve chamber, said U-shaped tube having its base portion in the area of greatest heat whereby liquefied gas which may accumulate therein is vaporized by said heat to assure flow of vaporized gas through said tube.

4. A liquefied gas storage and dispensing system including, a storage tank for holding liquefied gas under pressure, a secondary vaporizing chamber surrounding said tank and in heat exchanging relationship with the surrounding medium, means for admitting liquefied gas from the storage tank into said secondary chamber for vaporization therein, a valve chamber having communication with the secondary chamber ior' receiving vaporized gas therefrom and having a service outlet, a U-shaped tube establishing communication between the vapor space of the storage tank and said valve chamber, means for admitting liquefied gas from the storage tank to said valve chamber,

and a float valve in the valve chamber and actuated by the liquefied gas in said chamber for controlling admission of the vaporized gas from the vapor space of said storage tank to said valve chamber, the liquefied gas in the valve chamber forming a liquid seal between said float valve and U-shaped tube.

5. A liquefied gas storage and dispensing system including, a storage tank for holding lique fied gas under pressure, a secondary vaporizing chamber surrounding said tank and in heat exchanging relationship with the surrounding medium, means for admitting liquefied gas from the storage tank into said secondary chamber for vaporization therein, a valve chamber having communication with the secondary chamber for receiving vaporized gas therefrom and having a service outlet, a U-shaped tube having one arm extending upwardhr into the vapor space in the storage tank and its other arm extending axially upward within the valve chamber for establishing communication between the vapor space of the storage tank and said valve chamber, means for admitting liquefied gas from the storage tank to said valve chamber, and a float valve in the valve chamber telescoping the upwardly extending arm of the U-shaped tube and actuated by the liquefied gas in said chamber for controlling admission of the vaporized gas from the vapor space of said storage tank to said valve chamber.

6. A liquefied gas storage-and dispensing system including, a storage tank for holding liquefied gas under pressure, a secondary chamber surrounding said tank and in heat exchanging relationship with the surrounding medium, means for admitting liquefied gas from the storage tank into said secondary chamber for vaporization therein, a valve chamber having communication with the secondary chamber for receiving vaporized gas therefrom and having a service outlet, a U-shaped tube having one arm extending upwardly into the vapor space in the storage tank tank to said valve chamber, the liquified gas in the valve chamber forming a liquid seal between the float valve and the U-shaped tube, and a service line having a gas pressure regulator connected to the service outlet irom said valve chamber.

7. A liquefied gas storage and dispensing system including, a storage tank for holding liquefied gas under pressure, a vaporizing chamber in heat exchanging relationship with the surrounding medium, means for admitting liquefied gas from the storage tank into said vaporizing chamber for vaporization therein, a valve chamber,

in said chamber for controlling the admission of vaporized gas from the vapor space of said storage tank to said valve chamber. said valve means being operable to admit such vaporized gas from the storage tank to prevent liquefied gas from entering the service outlet from the valve chamber.

8. In a liquefied gas storage and dispensin system, a storage tank for holding liquefied gas under pressure, a gas vaporizing chamber, a valve housing having an inlet for admitting liquefied gas from the storage tank and an inlet for vaporized as from the vaporizing chamber, an upright conducfor in the housing for conducting vaporized gas from the storage tank into said housing, and a floating closure telescoping said upright conasrmar '5 ductor and floating on theliqueiied gas in said housing,. the contact oi the. liquefied gas with the floating closure forming a liquid seal to normally prevent .on or vaporized gas into the housing through the conductor and admitting vaporized gas irom the storage tank to said housing when the level of liqumed sea in the housing rises to a predetermined point.

9. In a liquefied gas storage and dispensing system, a storage tank for holding liquefied gas under pressure, a secondary chamber in heat exchanging reiationship with the surrounding medium and having communication with the liquefled gas in thestorage tank, a service outlet from said chamber, a conductor establishing communication between the vapor space .in the storage tank and the secondary chamber for admitting vaporized gas from said vapor space into said chamber; and means for utilizing a portion of the liquefied gas to form a seal normally closing on flow of vaporized gas through the conductor but chamber rises to a predetermined point. a.

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